Follow-along: Expand the graph

We have more than just listing details available in our graph. It also has bookings, reviews, users, and payments.

1. Open up the supergraph.yaml file.

2. Uncomment the information for the accounts, bookings, reviews, and payments subgraphs.

   supergraph.yaml

   subgraphs:
     listings:
       routing_url: https://rt-airlock-subgraphs-listings.herokuapp.com/
       schema:
         subgraph_url: https://rt-airlock-subgraphs-listings.herokuapp.com/
     accounts:
       routing_url: https://rt-airlock-subgraphs-accounts.herokuapp.com/
       schema:
         subgraph_url: https://rt-airlock-subgraphs-accounts.herokuapp.com/
     bookings:
       routing_url: https://rt-airlock-subgraphs-bookings.herokuapp.com/
       schema:
         subgraph_url: https://rt-airlock-subgraphs-bookings.herokuapp.com/
     reviews:
       routing_url: https://rt-airlock-subgraphs-reviews.herokuapp.com/
       schema:
         subgraph_url: https://rt-airlock-subgraphs-reviews.herokuapp.com/
     payments:
       routing_url: https://rt-airlock-subgraphs-payments.herokuapp.com/
       schema:
         subgraph_url: https://rt-airlock-subgraphs-payments.herokuapp.com/

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3. Save your changes and rover dev will restart, composing the new supergraph schema with all the available subgraphs.

To help us explore this larger graph, we'll enable introspection capabilities in our MCP server configuration.

GraphQL introspection & MCP

GraphQL introspection lets you query information about the schema and discover the types, fields, and operations available in the graph.

Introspection enables AI agents to craft their own queries, which can address user needs or questions more precisely than predefined queries.

But introspection comes with a downside: by providing all the details about a schema, we might introduce security concerns. Bad actors can end up seeing more than they should, which can result in unauthorized queries being executed against the graph.

In this workshop, we'll use introspection for an internal use case, as a developer using an agent to explore the graph so we can build new tools.

You can configure the following MCP server tools to enable introspection capabilities:

• introspect: Get the full GraphQL schema
• search: Search for types, fields, or other schema elements
• validate: Validate GraphQL queries without executing them
• execute: Execute GraphQL operations dynamically

Your MCP client will generally first try to introspect or search to retrieve information about the schema. Then, it will craft the operation it needs, use validate to check if the operation is valid, and finally execute the operation.

Follow-along: Enable introspection

1. Add the following introspection configuration to your mcp.yaml file:

   mcp.yaml

   introspection:
     execute:
       enabled: true
     introspect:
       enabled: true
       minify: true
     search:
       enabled: true
       minify: true
       index_memory_bytes: 50000000
       leaf_depth: 1
     validate:
       enabled: true

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   With this configuration, we've enabled all the introspection capabilities. We've also turned on minification to reduce the size of responses.

2. After saving your changes, restart the MCP server.

   rover dev --supergraph-config supergraph.yaml --mcp mcp.yaml --router-config router.yaml

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Follow-along: Test with MCP Inspector

1. Run the MCP Inspector again with npx @modelcontextprotocol/inspector. You should now see 4 additional tools: execute, introspect, search, and validate.

2. Try using the introspect tool in the MCP Inspector to see what it returns. You should get the complete GraphQL schema definition for your API.

3. Try using the search tool to search for the Booking type.

4. Try validating the GetFeaturedListings operation.

5. Try executing the GetFeaturedListings operation.

Follow-along: Test with Claude

Now let's restart Claude and test the new introspection capabilities:

1. Restart Claude Desktop to pick up the new tools
2. Check that Claude now has access to the introspection tools for your airlock-mcp server
3. Ask Claude: "What can you tell me about Airlock's schema?"
4. Claude will ask to use the introspect tool. Click Allow once.
5. Claude will return a detailed response outlining the schema structure, available types, fields, and operations.

Practice